Page 322 - Reservoir Formation Damage

302 Reservoir Formation Damage

The net mass rate of deposition of small particles within the filter cake
is given by:

C P21 - (12-136)
Rp2s = k d£ t
which is similar to Eq. 33 of Corapcioglu and Abboud (1990), but the
deposition and the mobilization terms are more consistently expressed.
The rate expressions given by Eqs. 12-134 through 136 for the deposi-
tion of the total (fine plus large) and fine particles of the slurry over the
progressing cake surface and the retention of the fine particles of the
flowing suspension within the cake matrix can be expressed in terms of
the volumetric rates, respectively, as (Civan, 1999b):

1-6 pi slurry
(12-137)

d2
1-e Pi Jslurry
(12-138)

-p2l (12-139)

In Eqs. 12-10 through 12, the slurry shear-stress, i s, acting over the
progressing cake surface is estimated using the Rabinowitsch-Mooney
equation (Metzner and Reed, 1955). This equation can be expressed for
linear and radial flow cases, respectively, as follows:

T =*'(8vV (12-140)

(12-141)

2
where k r and n are the consistency (dyne/cm /s"') and flow (dimension-
less) indices, which are equal to the fluid viscosity, jo, and unit for
Newtonian fluids, respectively, and v is the tangential velocity of the
slurry over the filter cake surface. For static filtration, v = 0 and therefore